Guangzhou, formerly known as Canton, has now seen two weeks of demonstrations by proponents of the Cantonese dialect, fearful that it may be eclipsed by Putonghua, the 'common language'.

Today Putonghua is spoken across China but that is a very recent phenomenon. Mao Zedong certainly didn't speak it. His Hunan dialect was unintelligible to most people. Similarly, Deng Xiaoping's Sichuan dialect was a real challenge to speakers of standard Putonghua.

Even the late Zhao Ziyang, the popular party leader put under house arrest for sympathising with the students in Tiananmen Square, was difficult to understand. His posthumous memoirs were based on secretly recorded tapes, which at times were difficult to decipher because of his heavy Henan accent.

So, even though the central government has been pushing Putonghua for more than half a century, it is only relatively recently that national leaders have been able to speak it well.

Even today, filmgoers often criticise producers for having old revolutionary leaders such as Mao speak perfect Putonghua in historical movies. However, the State Administration of Radio, Film and Television has decreed that national leaders, when depicted in historical films, should speak standard Putonghua, and so historical accuracy has lost out to political correctness.

While recent attention has focused on Cantonese, China is linguistically rich and the people of each region delight in their own dialects, cuisine and heritage. In fact, Chinese culture is a collection of separate cultures, each of which needs to be respected and preserved.

Like Cantonese, Shanghainese is a thriving dialect. One of the best known stand-up comedians in the country is Zhou Libo, whose routines are performed in Shanghainese. He even gets away with satirising political leaders in Beijing who, generally, don't understand the dialect.

A rare example of a Chinese film where the dialogue was almost entirely in a local dialect was Apart Together, which won the best screenplay award at the Berlin Film Festival this year. Starring the magnificent Lisa Lu, now in her 80s, its dialogue is in the Shanghai dialect from beginning to end, creating a sense of realism that would not be possible if filmed in Putonghua.

The film is politically correct in a different way; it is about a Kuomintang soldier who, in 1949, leaves his lover behind in Shanghai as he and other KMT troops retreat to Taiwan. Forty years later, his wife in Taiwan has died and his heart turns to his old flame in Shanghai, whom he decides to visit. Incredibly, her husband treats him like a long-lost relative and insists he stay in their home, where the visitor tries to lure the lady away from her husband and back to Taiwan.

While Cantonese speakers may fear that their dialect is imperiled by Putonghua, it is so dominant in Guangdong and Hong Kong that it has undermined other dialects. One letter writer in the Straits Times complained that the dominance of Cantonese has caused the 'decline of major dialects such as Hakka and Teochew' in Guangdong.

Even in Hong Kong, Cantonese did not used to be as dominant as it is today, possibly because of the large influx of refugees from various parts of China. Certainly, in the early 1950s, Rediffusion - the predecessor of ATV - broadcast Chinese news each night not just in Cantonese but also in Putonghua and the Chaozhou dialect of eastern Guangdong. Today that dialect is nowhere near as prevalent. Young people of Chaozhou descent, it seems, prefer to speak Cantonese and have largely abandoned their ancestral dialect.